bin/sh/jobs.c

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Kenneth Almquist.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * @(#)jobs.c   8.5 (Berkeley) 5/4/95
  37  * $FreeBSD: src/bin/sh/jobs.c,v 1.72 2006/10/07 16:51:16 stefanf Exp $
  38  * $DragonFly: src/bin/sh/jobs.c,v 1.9 2007/01/13 21:27:45 pavalos Exp $
  39  */
  40
  41 #include <fcntl.h>
  42 #include <signal.h>
  43 #include <errno.h>
  44 #include <paths.h>
  45 #include <unistd.h>
  46 #include <stdlib.h>
  47 #include <sys/param.h>
  48 #include <sys/wait.h>
  49 #include <sys/time.h>
  50 #include <sys/resource.h>
  51 #include <paths.h>
  52 #include <sys/ioctl.h>
  53
  54 #include "shell.h"
  55 #if JOBS
  56 #include <termios.h>
  57 #undef CEOF                     /* syntax.h redefines this */
  58 #endif
  59 #include "redir.h"
  60 #include "show.h"
  61 #include "main.h"
  62 #include "parser.h"
  63 #include "nodes.h"
  64 #include "jobs.h"
  65 #include "options.h"
  66 #include "trap.h"
  67 #include "syntax.h"
  68 #include "input.h"
  69 #include "output.h"
  70 #include "memalloc.h"
  71 #include "error.h"
  72 #include "mystring.h"
  73
  74
  75 STATIC struct job *jobtab;      /* array of jobs */
  76 STATIC int njobs;               /* size of array */
  77 MKINIT pid_t backgndpid = -1;   /* pid of last background process */
  78 #if JOBS
  79 STATIC struct job *jobmru;      /* most recently used job list */
  80 STATIC pid_t initialpgrp;       /* pgrp of shell on invocation */
  81 #endif
  82 int in_waitcmd = 0;             /* are we in waitcmd()? */
  83 int in_dowait = 0;              /* are we in dowait()? */
  84 volatile sig_atomic_t breakwaitcmd = 0; /* should wait be terminated? */
  85 static int ttyfd = -1;
  86
  87 #if JOBS
  88 STATIC void restartjob(struct job *);
  89 #endif
  90 STATIC void freejob(struct job *);
  91 STATIC struct job *getjob(char *);
  92 STATIC pid_t dowait(int, struct job *);
  93 STATIC pid_t waitproc(int, int *);
  94 STATIC void cmdtxt(union node *);
  95 STATIC void cmdputs(const char *);
  96 #if JOBS
  97 STATIC void setcurjob(struct job *);
  98 STATIC void deljob(struct job *);
  99 STATIC struct job *getcurjob(struct job *);
 100 #endif
 101 STATIC void showjob(struct job *, pid_t, int);
 102
 103
 104 /*
 105  * Turn job control on and off.
 106  */
 107
 108 MKINIT int jobctl;
 109
 110 #if JOBS
 111 void
 112 setjobctl(int on)
 113 {
 114         int i;
 115
 116         if (on == jobctl || rootshell == 0)
 117                 return;
 118         if (on) {
 119                 if (ttyfd != -1)
 120                         close(ttyfd);
 121                 if ((ttyfd = open(_PATH_TTY, O_RDWR)) < 0) {
 122                         i = 0;
 123                         while (i <= 2 && !isatty(i))
 124                                 i++;
 125                         if (i > 2 || (ttyfd = fcntl(i, F_DUPFD, 10)) < 0)
 126                                 goto out;
 127                 }
 128                 if (ttyfd < 10) {
 129                         /*
 130                          * Keep our TTY file descriptor out of the way of
 131                          * the user's redirections.
 132                          */
 133                         if ((i = fcntl(ttyfd, F_DUPFD, 10)) < 0) {
 134                                 close(ttyfd);
 135                                 ttyfd = -1;
 136                                 goto out;
 137                         }
 138                         close(ttyfd);
 139                         ttyfd = i;
 140                 }
 141                 if (fcntl(ttyfd, F_SETFD, FD_CLOEXEC) < 0) {
 142                         close(ttyfd);
 143                         ttyfd = -1;
 144                         goto out;
 145                 }
 146                 do { /* while we are in the background */
 147                         initialpgrp = tcgetpgrp(ttyfd);
 148                         if (initialpgrp < 0) {
 149 out:                            out2str("sh: can't access tty; job control turned off\n");
 150                                 mflag = 0;
 151                                 return;
 152                         }
 153                         if (initialpgrp == -1)
 154                                 initialpgrp = getpgrp();
 155                         else if (initialpgrp != getpgrp()) {
 156                                 killpg(0, SIGTTIN);
 157                                 continue;
 158                         }
 159                 } while (0);
 160                 setsignal(SIGTSTP);
 161                 setsignal(SIGTTOU);
 162                 setsignal(SIGTTIN);
 163                 setpgid(0, rootpid);
 164                 tcsetpgrp(ttyfd, rootpid);
 165         } else { /* turning job control off */
 166                 setpgid(0, initialpgrp);
 167                 tcsetpgrp(ttyfd, initialpgrp);
 168                 close(ttyfd);
 169                 ttyfd = -1;
 170                 setsignal(SIGTSTP);
 171                 setsignal(SIGTTOU);
 172                 setsignal(SIGTTIN);
 173         }
 174         jobctl = on;
 175 }
 176 #endif
 177
 178
 179 #ifdef mkinit
 180 INCLUDE <sys/types.h>
 181 INCLUDE <stdlib.h>
 182
 183 SHELLPROC {
 184         backgndpid = -1;
 185 #if JOBS
 186         jobctl = 0;
 187 #endif
 188 }
 189
 190 #endif
 191
 192
 193
 194 #if JOBS
 195 int
 196 fgcmd(int argc __unused, char **argv)
 197 {
 198         struct job *jp;
 199         pid_t pgrp;
 200         int status;
 201
 202         jp = getjob(argv[1]);
 203         if (jp->jobctl == 0)
 204                 error("job not created under job control");
 205         out1str(jp->ps[0].cmd);
 206         out1c('\n');
 207         flushout(&output);
 208         pgrp = jp->ps[0].pid;
 209         tcsetpgrp(ttyfd, pgrp);
 210         restartjob(jp);
 211         jp->foreground = 1;
 212         INTOFF;
 213         status = waitforjob(jp, (int *)NULL);
 214         INTON;
 215         return status;
 216 }
 217
 218
 219 int
 220 bgcmd(int argc, char **argv)
 221 {
 222         char s[64];
 223         struct job *jp;
 224
 225         do {
 226                 jp = getjob(*++argv);
 227                 if (jp->jobctl == 0)
 228                         error("job not created under job control");
 229                 if (jp->state == JOBDONE)
 230                         continue;
 231                 restartjob(jp);
 232                 jp->foreground = 0;
 233                 fmtstr(s, 64, "[%td] ", jp - jobtab + 1);
 234                 out1str(s);
 235                 out1str(jp->ps[0].cmd);
 236                 out1c('\n');
 237         } while (--argc > 1);
 238         return 0;
 239 }
 240
 241
 242 STATIC void
 243 restartjob(struct job *jp)
 244 {
 245         struct procstat *ps;
 246         int i;
 247
 248         if (jp->state == JOBDONE)
 249                 return;
 250         setcurjob(jp);
 251         INTOFF;
 252         killpg(jp->ps[0].pid, SIGCONT);
 253         for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
 254                 if (WIFSTOPPED(ps->status)) {
 255                         ps->status = -1;
 256                         jp->state = 0;
 257                 }
 258         }
 259         INTON;
 260 }
 261 #endif
 262
 263
 264 int
 265 jobscmd(int argc, char *argv[])
 266 {
 267         char *id;
 268         int ch, mode;
 269
 270         optind = optreset = 1;
 271         opterr = 0;
 272         mode = SHOWJOBS_DEFAULT;
 273         while ((ch = getopt(argc, argv, "lps")) != -1) {
 274                 switch (ch) {
 275                 case 'l':
 276                         mode = SHOWJOBS_VERBOSE;
 277                         break;
 278                 case 'p':
 279                         mode = SHOWJOBS_PGIDS;
 280                         break;
 281                 case 's':
 282                         mode = SHOWJOBS_PIDS;
 283                         break;
 284                 case '?':
 285                 default:
 286                         error("unknown option: -%c", optopt);
 287                 }
 288         }
 289         argc -= optind;
 290         argv += optind;
 291
 292         if (argc == 0)
 293                 showjobs(0, mode);
 294         else
 295                 while ((id = *argv++) != NULL)
 296                         showjob(getjob(id), 0, mode);
 297
 298         return (0);
 299 }
 300
 301 STATIC void
 302 showjob(struct job *jp, pid_t pid, int mode)
 303 {
 304         char s[64];
 305         struct procstat *ps;
 306         struct job *j;
 307         int col, curr, i, jobno, prev, procno;
 308         pid_t ppid;
 309         char c;
 310
 311         procno = (mode == SHOWJOBS_PGIDS) ? 1 : jp->nprocs;
 312         jobno = jp - jobtab + 1;
 313         curr = prev = 0;
 314 #if JOBS
 315         if ((j = getcurjob(NULL)) != NULL) {
 316                 curr = j - jobtab + 1;
 317                 if ((j = getcurjob(j)) != NULL)
 318                         prev = j - jobtab + 1;
 319         }
 320 #endif
 321         for (ps = jp->ps ; ; ps++) {    /* for each process */
 322                 if (mode == SHOWJOBS_PIDS || mode == SHOWJOBS_PGIDS) {
 323                         ppid = (mode == SHOWJOBS_PIDS) ? ps->pid :
 324                             getpgid(ps->pid);
 325                         out1fmt("%d\n", (int)ppid);
 326                         goto skip;
 327                 }
 328                 if (mode != SHOWJOBS_VERBOSE && ps != jp->ps && pid == 0)
 329                         goto skip;
 330                 if (pid != 0 && pid != ps->pid)
 331                         goto skip;
 332                 if (jobno == curr && ps == jp->ps)
 333                         c = '+';
 334                 else if (jobno == prev && ps == jp->ps)
 335                         c = '-';
 336                 else
 337                         c = ' ';
 338                 if (ps == jp->ps)
 339                         fmtstr(s, 64, "[%d] %c ", jobno, c);
 340                 else
 341                         fmtstr(s, 64, "    %c ", c);
 342                 out1str(s);
 343                 col = strlen(s);
 344                 if (mode == SHOWJOBS_VERBOSE) {
 345                         fmtstr(s, 64, "%d ", (int)ps->pid);
 346                         out1str(s);
 347                         col += strlen(s);
 348                 }
 349                 s[0] = '\0';
 350                 if (ps != jp->ps) {
 351                         *s = '\0';
 352                 } else if (ps->status == -1) {
 353                         strcpy(s, "Running");
 354                 } else if (WIFEXITED(ps->status)) {
 355                         if (WEXITSTATUS(ps->status) == 0)
 356                                 strcpy(s, "Done");
 357                         else
 358                                 fmtstr(s, 64, "Done (%d)",
 359                                     WEXITSTATUS(ps->status));
 360                 } else {
 361 #if JOBS
 362                         if (WIFSTOPPED(ps->status))
 363                                 i = WSTOPSIG(ps->status);
 364                         else
 365 #endif
 366                                 i = WTERMSIG(ps->status);
 367                         if ((i & 0x7F) < sys_nsig && sys_siglist[i & 0x7F])
 368                                 scopy(sys_siglist[i & 0x7F], s);
 369                         else
 370                                 fmtstr(s, 64, "Signal %d", i & 0x7F);
 371                         if (WCOREDUMP(ps->status))
 372                                 strcat(s, " (core dumped)");
 373                 }
 374                 out1str(s);
 375                 col += strlen(s);
 376                 do {
 377                         out1c(' ');
 378                         col++;
 379                 } while (col < 30);
 380                 out1str(ps->cmd);
 381                 out1c('\n');
 382 skip:           if (--procno <= 0)
 383                         break;
 384         }
 385 }
 386
 387 /*
 388  * Print a list of jobs.  If "change" is nonzero, only print jobs whose
 389  * statuses have changed since the last call to showjobs.
 390  *
 391  * If the shell is interrupted in the process of creating a job, the
 392  * result may be a job structure containing zero processes.  Such structures
 393  * will be freed here.
 394  */
 395
 396 void
 397 showjobs(int change, int mode)
 398 {
 399         int jobno;
 400         struct job *jp;
 401
 402         TRACE(("showjobs(%d) called\n", change));
 403         while (dowait(0, (struct job *)NULL) > 0);
 404         for (jobno = 1, jp = jobtab ; jobno <= njobs ; jobno++, jp++) {
 405                 if (! jp->used)
 406                         continue;
 407                 if (jp->nprocs == 0) {
 408                         freejob(jp);
 409                         continue;
 410                 }
 411                 if (change && ! jp->changed)
 412                         continue;
 413                 showjob(jp, 0, mode);
 414                 jp->changed = 0;
 415                 if (jp->state == JOBDONE) {
 416                         freejob(jp);
 417                 }
 418         }
 419 }
 420
 421
 422 /*
 423  * Mark a job structure as unused.
 424  */
 425
 426 STATIC void
 427 freejob(struct job *jp)
 428 {
 429         struct procstat *ps;
 430         int i;
 431
 432         INTOFF;
 433         for (i = jp->nprocs, ps = jp->ps ; --i >= 0 ; ps++) {
 434                 if (ps->cmd != nullstr)
 435                         ckfree(ps->cmd);
 436         }
 437         if (jp->ps != &jp->ps0)
 438                 ckfree(jp->ps);
 439         jp->used = 0;
 440 #if JOBS
 441         deljob(jp);
 442 #endif
 443         INTON;
 444 }
 445
 446
 447
 448 int
 449 waitcmd(int argc, char **argv)
 450 {
 451         struct job *job;
 452         int status, retval;
 453         struct job *jp;
 454
 455         if (argc > 1) {
 456                 job = getjob(argv[1]);
 457         } else {
 458                 job = NULL;
 459         }
 460
 461         /*
 462          * Loop until a process is terminated or stopped, or a SIGINT is
 463          * received.
 464          */
 465
 466         in_waitcmd++;
 467         do {
 468                 if (job != NULL) {
 469                         if (job->state) {
 470                                 status = job->ps[job->nprocs - 1].status;
 471                                 if (WIFEXITED(status))
 472                                         retval = WEXITSTATUS(status);
 473 #if JOBS
 474                                 else if (WIFSTOPPED(status))
 475                                         retval = WSTOPSIG(status) + 128;
 476 #endif
 477                                 else
 478                                         retval = WTERMSIG(status) + 128;
 479                                 if (! iflag)
 480                                         freejob(job);
 481                                 in_waitcmd--;
 482                                 return retval;
 483                         }
 484                 } else {
 485                         for (jp = jobtab ; ; jp++) {
 486                                 if (jp >= jobtab + njobs) {     /* no running procs */
 487                                         in_waitcmd--;
 488                                         return 0;
 489                                 }
 490                                 if (jp->used && jp->state == 0)
 491                                         break;
 492                         }
 493                 }
 494         } while (dowait(1, (struct job *)NULL) != -1);
 495         in_waitcmd--;
 496
 497         return 0;
 498 }
 499
 500
 501
 502 int
 503 jobidcmd(int argc __unused, char **argv)
 504 {
 505         struct job *jp;
 506         int i;
 507
 508         jp = getjob(argv[1]);
 509         for (i = 0 ; i < jp->nprocs ; ) {
 510                 out1fmt("%d", (int)jp->ps[i].pid);
 511                 out1c(++i < jp->nprocs? ' ' : '\n');
 512         }
 513         return 0;
 514 }
 515
 516
 517
 518 /*
 519  * Convert a job name to a job structure.
 520  */
 521
 522 STATIC struct job *
 523 getjob(char *name)
 524 {
 525         int jobno;
 526         struct job *found, *jp;
 527         pid_t pid;
 528         int i;
 529
 530         if (name == NULL) {
 531 #if JOBS
 532 currentjob:     if ((jp = getcurjob(NULL)) == NULL)
 533                         error("No current job");
 534                 return (jp);
 535 #else
 536                 error("No current job");
 537 #endif
 538         } else if (name[0] == '%') {
 539                 if (is_digit(name[1])) {
 540                         jobno = number(name + 1);
 541                         if (jobno > 0 && jobno <= njobs
 542                          && jobtab[jobno - 1].used != 0)
 543                                 return &jobtab[jobno - 1];
 544 #if JOBS
 545                 } else if (name[1] == '%' && name[2] == '\0') {
 546                         goto currentjob;
 547                 } else if (name[1] == '+' && name[2] == '\0') {
 548                         goto currentjob;
 549                 } else if (name[1] == '-' && name[2] == '\0') {
 550                         if ((jp = getcurjob(NULL)) == NULL ||
 551                             (jp = getcurjob(jp)) == NULL)
 552                                 error("No previous job");
 553                         return (jp);
 554 #endif
 555                 } else if (name[1] == '?') {
 556                         found = NULL;
 557                         for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 558                                 if (jp->used && jp->nprocs > 0
 559                                  && strstr(jp->ps[0].cmd, name + 2) != NULL) {
 560                                         if (found)
 561                                                 error("%s: ambiguous", name);
 562                                         found = jp;
 563                                 }
 564                         }
 565                         if (found != NULL)
 566                                 return (found);
 567                 } else {
 568                         found = NULL;
 569                         for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 570                                 if (jp->used && jp->nprocs > 0
 571                                  && prefix(name + 1, jp->ps[0].cmd)) {
 572                                         if (found)
 573                                                 error("%s: ambiguous", name);
 574                                         found = jp;
 575                                 }
 576                         }
 577                         if (found)
 578                                 return found;
 579                 }
 580         } else if (is_number(name)) {
 581                 pid = (pid_t)number(name);
 582                 for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
 583                         if (jp->used && jp->nprocs > 0
 584                          && jp->ps[jp->nprocs - 1].pid == pid)
 585                                 return jp;
 586                 }
 587         }
 588         error("No such job: %s", name);
 589         /*NOTREACHED*/
 590         return NULL;
 591 }
 592
 593
 594
 595 /*
 596  * Return a new job structure,
 597  */
 598
 599 struct job *
 600 makejob(union node *node __unused, int nprocs)
 601 {
 602         int i;
 603         struct job *jp;
 604
 605         for (i = njobs, jp = jobtab ; ; jp++) {
 606                 if (--i < 0) {
 607                         INTOFF;
 608                         if (njobs == 0) {
 609                                 jobtab = ckmalloc(4 * sizeof jobtab[0]);
 610 #if JOBS
 611                                 jobmru = NULL;
 612 #endif
 613                         } else {
 614                                 jp = ckmalloc((njobs + 4) * sizeof jobtab[0]);
 615                                 memcpy(jp, jobtab, njobs * sizeof jp[0]);
 616 #if JOBS
 617                                 /* Relocate `next' pointers and list head */
 618                                 if (jobmru != NULL)
 619                                         jobmru = &jp[jobmru - jobtab];
 620                                 for (i = 0; i < njobs; i++)
 621                                         if (jp[i].next != NULL)
 622                                                 jp[i].next = &jp[jp[i].next -
 623                                                     jobtab];
 624 #endif
 625                                 /* Relocate `ps' pointers */
 626                                 for (i = 0; i < njobs; i++)
 627                                         if (jp[i].ps == &jobtab[i].ps0)
 628                                                 jp[i].ps = &jp[i].ps0;
 629                                 ckfree(jobtab);
 630                                 jobtab = jp;
 631                         }
 632                         jp = jobtab + njobs;
 633                         for (i = 4 ; --i >= 0 ; jobtab[njobs++].used = 0);
 634                         INTON;
 635                         break;
 636                 }
 637                 if (jp->used == 0)
 638                         break;
 639         }
 640         INTOFF;
 641         jp->state = 0;
 642         jp->used = 1;
 643         jp->changed = 0;
 644         jp->nprocs = 0;
 645         jp->foreground = 0;
 646 #if JOBS
 647         jp->jobctl = jobctl;
 648         jp->next = NULL;
 649 #endif
 650         if (nprocs > 1) {
 651                 jp->ps = ckmalloc(nprocs * sizeof (struct procstat));
 652         } else {
 653                 jp->ps = &jp->ps0;
 654         }
 655         INTON;
 656         TRACE(("makejob(%p, %d) returns %%%d\n", (void *)node, nprocs,
 657             jp - jobtab + 1));
 658         return jp;
 659 }
 660
 661 #if JOBS
 662 STATIC void
 663 setcurjob(struct job *cj)
 664 {
 665         struct job *jp, *prev;
 666
 667         for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
 668                 if (jp == cj) {
 669                         if (prev != NULL)
 670                                 prev->next = jp->next;
 671                         else
 672                                 jobmru = jp->next;
 673                         jp->next = jobmru;
 674                         jobmru = cj;
 675                         return;
 676                 }
 677         }
 678         cj->next = jobmru;
 679         jobmru = cj;
 680 }
 681
 682 STATIC void
 683 deljob(struct job *j)
 684 {
 685         struct job *jp, *prev;
 686
 687         for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
 688                 if (jp == j) {
 689                         if (prev != NULL)
 690                                 prev->next = jp->next;
 691                         else
 692                                 jobmru = jp->next;
 693                         return;
 694                 }
 695         }
 696 }
 697
 698 /*
 699  * Return the most recently used job that isn't `nj', and preferably one
 700  * that is stopped.
 701  */
 702 STATIC struct job *
 703 getcurjob(struct job *nj)
 704 {
 705         struct job *jp;
 706
 707         /* Try to find a stopped one.. */
 708         for (jp = jobmru; jp != NULL; jp = jp->next)
 709                 if (jp->used && jp != nj && jp->state == JOBSTOPPED)
 710                         return (jp);
 711         /* Otherwise the most recently used job that isn't `nj' */
 712         for (jp = jobmru; jp != NULL; jp = jp->next)
 713                 if (jp->used && jp != nj)
 714                         return (jp);
 715
 716         return (NULL);
 717 }
 718
 719 #endif
 720
 721 /*
 722  * Fork of a subshell.  If we are doing job control, give the subshell its
 723  * own process group.  Jp is a job structure that the job is to be added to.
 724  * N is the command that will be evaluated by the child.  Both jp and n may
 725  * be NULL.  The mode parameter can be one of the following:
 726  *      FORK_FG - Fork off a foreground process.
 727  *      FORK_BG - Fork off a background process.
 728  *      FORK_NOJOB - Like FORK_FG, but don't give the process its own
 729  *                   process group even if job control is on.
 730  *
 731  * When job control is turned off, background processes have their standard
 732  * input redirected to /dev/null (except for the second and later processes
 733  * in a pipeline).
 734  */
 735
 736 pid_t
 737 forkshell(struct job *jp, union node *n, int mode)
 738 {
 739         pid_t pid;
 740         pid_t pgrp;
 741
 742         TRACE(("forkshell(%%%d, %p, %d) called\n", jp - jobtab, (void *)n,
 743             mode));
 744         INTOFF;
 745         flushall();
 746         pid = fork();
 747         if (pid == -1) {
 748                 TRACE(("Fork failed, errno=%d\n", errno));
 749                 INTON;
 750                 error("Cannot fork: %s", strerror(errno));
 751         }
 752         if (pid == 0) {
 753                 struct job *p;
 754                 int wasroot;
 755                 int i;
 756
 757                 TRACE(("Child shell %d\n", (int)getpid()));
 758                 wasroot = rootshell;
 759                 rootshell = 0;
 760                 closescript();
 761                 INTON;
 762                 clear_traps();
 763 #if JOBS
 764                 jobctl = 0;             /* do job control only in root shell */
 765                 if (wasroot && mode != FORK_NOJOB && mflag) {
 766                         if (jp == NULL || jp->nprocs == 0)
 767                                 pgrp = getpid();
 768                         else
 769                                 pgrp = jp->ps[0].pid;
 770                         if (setpgid(0, pgrp) == 0 && mode == FORK_FG) {
 771                                 /*** this causes superfluous TIOCSPGRPS ***/
 772                                 if (tcsetpgrp(ttyfd, pgrp) < 0)
 773                                         error("tcsetpgrp failed, errno=%d", errno);
 774                         }
 775                         setsignal(SIGTSTP);
 776                         setsignal(SIGTTOU);
 777                 } else if (mode == FORK_BG) {
 778                         ignoresig(SIGINT);
 779                         ignoresig(SIGQUIT);
 780                         if ((jp == NULL || jp->nprocs == 0) &&
 781                             ! fd0_redirected_p ()) {
 782                                 close(0);
 783                                 if (open(_PATH_DEVNULL, O_RDONLY) != 0)
 784                                         error("Can't open %s: %s",
 785                                             _PATH_DEVNULL, strerror(errno));
 786                         }
 787                 }
 788 #else
 789                 if (mode == FORK_BG) {
 790                         ignoresig(SIGINT);
 791                         ignoresig(SIGQUIT);
 792                         if ((jp == NULL || jp->nprocs == 0) &&
 793                             ! fd0_redirected_p ()) {
 794                                 close(0);
 795                                 if (open(_PATH_DEVNULL, O_RDONLY) != 0)
 796                                         error("Can't open %s: %s",
 797                                             _PATH_DEVNULL, strerror(errno));
 798                         }
 799                 }
 800 #endif
 801                 INTOFF;
 802                 for (i = njobs, p = jobtab ; --i >= 0 ; p++)
 803                         if (p->used)
 804                                 freejob(p);
 805                 INTON;
 806                 if (wasroot && iflag) {
 807                         setsignal(SIGINT);
 808                         setsignal(SIGQUIT);
 809                         setsignal(SIGTERM);
 810                 }
 811                 return pid;
 812         }
 813         if (rootshell && mode != FORK_NOJOB && mflag) {
 814                 if (jp == NULL || jp->nprocs == 0)
 815                         pgrp = pid;
 816                 else
 817                         pgrp = jp->ps[0].pid;
 818                 setpgid(pid, pgrp);
 819         }
 820         if (mode == FORK_BG)
 821                 backgndpid = pid;               /* set $! */
 822         if (jp) {
 823                 struct procstat *ps = &jp->ps[jp->nprocs++];
 824                 ps->pid = pid;
 825                 ps->status = -1;
 826                 ps->cmd = nullstr;
 827                 if (iflag && rootshell && n)
 828                         ps->cmd = commandtext(n);
 829                 jp->foreground = mode == FORK_FG;
 830 #if JOBS
 831                 setcurjob(jp);
 832 #endif
 833         }
 834         INTON;
 835         TRACE(("In parent shell:  child = %d\n", (int)pid));
 836         return pid;
 837 }
 838
 839
 840
 841 /*
 842  * Wait for job to finish.
 843  *
 844  * Under job control we have the problem that while a child process is
 845  * running interrupts generated by the user are sent to the child but not
 846  * to the shell.  This means that an infinite loop started by an inter-
 847  * active user may be hard to kill.  With job control turned off, an
 848  * interactive user may place an interactive program inside a loop.  If
 849  * the interactive program catches interrupts, the user doesn't want
 850  * these interrupts to also abort the loop.  The approach we take here
 851  * is to have the shell ignore interrupt signals while waiting for a
 852  * foreground process to terminate, and then send itself an interrupt
 853  * signal if the child process was terminated by an interrupt signal.
 854  * Unfortunately, some programs want to do a bit of cleanup and then
 855  * exit on interrupt; unless these processes terminate themselves by
 856  * sending a signal to themselves (instead of calling exit) they will
 857  * confuse this approach.
 858  */
 859
 860 int
 861 waitforjob(struct job *jp, int *origstatus)
 862 {
 863 #if JOBS
 864         pid_t mypgrp = getpgrp();
 865 #endif
 866         int status;
 867         int st;
 868
 869         INTOFF;
 870         TRACE(("waitforjob(%%%d) called\n", jp - jobtab + 1));
 871         while (jp->state == 0)
 872                 if (dowait(1, jp) == -1)
 873                         dotrap();
 874 #if JOBS
 875         if (jp->jobctl) {
 876                 if (tcsetpgrp(ttyfd, mypgrp) < 0)
 877                         error("tcsetpgrp failed, errno=%d\n", errno);
 878         }
 879         if (jp->state == JOBSTOPPED)
 880                 setcurjob(jp);
 881 #endif
 882         status = jp->ps[jp->nprocs - 1].status;
 883         if (origstatus != NULL)
 884                 *origstatus = status;
 885         /* convert to 8 bits */
 886         if (WIFEXITED(status))
 887                 st = WEXITSTATUS(status);
 888 #if JOBS
 889         else if (WIFSTOPPED(status))
 890                 st = WSTOPSIG(status) + 128;
 891 #endif
 892         else
 893                 st = WTERMSIG(status) + 128;
 894         if (! JOBS || jp->state == JOBDONE)
 895                 freejob(jp);
 896         if (int_pending()) {
 897                 if (WIFSIGNALED(status) && WTERMSIG(status) == SIGINT)
 898                         kill(getpid(), SIGINT);
 899                 else
 900                         CLEAR_PENDING_INT;
 901         }
 902         INTON;
 903         return st;
 904 }
 905
 906
 907
 908 /*
 909  * Wait for a process to terminate.
 910  */
 911
 912 STATIC pid_t
 913 dowait(int block, struct job *job)
 914 {
 915         pid_t pid;
 916         int status;
 917         struct procstat *sp;
 918         struct job *jp;
 919         struct job *thisjob;
 920         int done;
 921         int stopped;
 922         int sig;
 923         int i;
 924
 925         in_dowait++;
 926         TRACE(("dowait(%d) called\n", block));
 927         do {
 928                 pid = waitproc(block, &status);
 929                 TRACE(("wait returns %d, status=%d\n", (int)pid, status));
 930         } while ((pid == -1 && errno == EINTR && breakwaitcmd == 0) ||
 931                  (pid > 0 && WIFSTOPPED(status) && !iflag));
 932         in_dowait--;
 933         if (pid == -1 && errno == ECHILD && job != NULL)
 934                 job->state = JOBDONE;
 935         if (breakwaitcmd != 0) {
 936                 breakwaitcmd = 0;
 937                 /*
 938                  * Do not early terminate if the pid is positive, else the
 939                  * job will not be properly recorded.
 940                  */
 941                 if (pid <= 0)
 942                         return -1;
 943         }
 944         if (pid <= 0)
 945                 return pid;
 946         INTOFF;
 947         thisjob = NULL;
 948         for (jp = jobtab ; jp < jobtab + njobs ; jp++) {
 949                 if (jp->used) {
 950                         done = 1;
 951                         stopped = 1;
 952                         for (sp = jp->ps ; sp < jp->ps + jp->nprocs ; sp++) {
 953                                 if (sp->pid == -1)
 954                                         continue;
 955                                 if (sp->pid == pid) {
 956                                         TRACE(("Changing status of proc %d from 0x%x to 0x%x\n",
 957                                                    (int)pid, sp->status,
 958                                                    status));
 959                                         sp->status = status;
 960                                         thisjob = jp;
 961                                 }
 962                                 if (sp->status == -1)
 963                                         stopped = 0;
 964                                 else if (WIFSTOPPED(sp->status))
 965                                         done = 0;
 966                         }
 967                         if (stopped) {          /* stopped or done */
 968                                 int state = done? JOBDONE : JOBSTOPPED;
 969                                 if (jp->state != state) {
 970                                         TRACE(("Job %d: changing state from %d to %d\n", jp - jobtab + 1, jp->state, state));
 971                                         jp->state = state;
 972 #if JOBS
 973                                         if (done)
 974                                                 deljob(jp);
 975 #endif
 976                                 }
 977                         }
 978                 }
 979         }
 980         INTON;
 981         if (! rootshell || ! iflag || (job && thisjob == job)) {
 982 #if JOBS
 983                 if (WIFSTOPPED(status))
 984                         sig = WSTOPSIG(status);
 985                 else
 986 #endif
 987                 {
 988                         if (WIFEXITED(status))
 989                                 sig = 0;
 990                         else
 991                                 sig = WTERMSIG(status);
 992                 }
 993                 if (sig != 0 && sig != SIGINT && sig != SIGPIPE) {
 994                         if (!mflag ||
 995                             (thisjob->foreground && !WIFSTOPPED(status))) {
 996                                 i = WTERMSIG(status);
 997                                 if ((i & 0x7F) < sys_nsig && sys_siglist[i & 0x7F])
 998                                         out1str(sys_siglist[i & 0x7F]);
 999                                 else
1000                                         out1fmt("Signal %d", i & 0x7F);
1001                                 if (WCOREDUMP(status))
1002                                         out1str(" (core dumped)");
1003                                 out1c('\n');
1004                         } else
1005                                 showjob(thisjob, pid, SHOWJOBS_DEFAULT);
1006                 }
1007         } else {
1008                 TRACE(("Not printing status, rootshell=%d, job=%p\n", rootshell, job));
1009                 if (thisjob)
1010                         thisjob->changed = 1;
1011         }
1012         return pid;
1013 }
1014
1015
1016
1017 /*
1018  * Do a wait system call.  If job control is compiled in, we accept
1019  * stopped processes.  If block is zero, we return a value of zero
1020  * rather than blocking.
1021  */
1022 STATIC pid_t
1023 waitproc(int block, int *status)
1024 {
1025         int flags;
1026
1027 #if JOBS
1028         flags = WUNTRACED;
1029 #else
1030         flags = 0;
1031 #endif
1032         if (block == 0)
1033                 flags |= WNOHANG;
1034         return wait3(status, flags, (struct rusage *)NULL);
1035 }
1036
1037 /*
1038  * return 1 if there are stopped jobs, otherwise 0
1039  */
1040 int job_warning = 0;
1041 int
1042 stoppedjobs(void)
1043 {
1044         int jobno;
1045         struct job *jp;
1046
1047         if (job_warning)
1048                 return (0);
1049         for (jobno = 1, jp = jobtab; jobno <= njobs; jobno++, jp++) {
1050                 if (jp->used == 0)
1051                         continue;
1052                 if (jp->state == JOBSTOPPED) {
1053                         out2str("You have stopped jobs.\n");
1054                         job_warning = 2;
1055                         return (1);
1056                 }
1057         }
1058
1059         return (0);
1060 }
1061
1062 /*
1063  * Return a string identifying a command (to be printed by the
1064  * jobs command.
1065  */
1066
1067 STATIC char *cmdnextc;
1068 STATIC int cmdnleft;
1069 #define MAXCMDTEXT      200
1070
1071 char *
1072 commandtext(union node *n)
1073 {
1074         char *name;
1075
1076         cmdnextc = name = ckmalloc(MAXCMDTEXT);
1077         cmdnleft = MAXCMDTEXT - 4;
1078         cmdtxt(n);
1079         *cmdnextc = '\0';
1080         return name;
1081 }
1082
1083
1084 STATIC void
1085 cmdtxt(union node *n)
1086 {
1087         union node *np;
1088         struct nodelist *lp;
1089         const char *p;
1090         int i;
1091         char s[2];
1092
1093         if (n == NULL)
1094                 return;
1095         switch (n->type) {
1096         case NSEMI:
1097                 cmdtxt(n->nbinary.ch1);
1098                 cmdputs("; ");
1099                 cmdtxt(n->nbinary.ch2);
1100                 break;
1101         case NAND:
1102                 cmdtxt(n->nbinary.ch1);
1103                 cmdputs(" && ");
1104                 cmdtxt(n->nbinary.ch2);
1105                 break;
1106         case NOR:
1107                 cmdtxt(n->nbinary.ch1);
1108                 cmdputs(" || ");
1109                 cmdtxt(n->nbinary.ch2);
1110                 break;
1111         case NPIPE:
1112                 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
1113                         cmdtxt(lp->n);
1114                         if (lp->next)
1115                                 cmdputs(" | ");
1116                 }
1117                 break;
1118         case NSUBSHELL:
1119                 cmdputs("(");
1120                 cmdtxt(n->nredir.n);
1121                 cmdputs(")");
1122                 break;
1123         case NREDIR:
1124         case NBACKGND:
1125                 cmdtxt(n->nredir.n);
1126                 break;
1127         case NIF:
1128                 cmdputs("if ");
1129                 cmdtxt(n->nif.test);
1130                 cmdputs("; then ");
1131                 cmdtxt(n->nif.ifpart);
1132                 cmdputs("...");
1133                 break;
1134         case NWHILE:
1135                 cmdputs("while ");
1136                 goto until;
1137         case NUNTIL:
1138                 cmdputs("until ");
1139 until:
1140                 cmdtxt(n->nbinary.ch1);
1141                 cmdputs("; do ");
1142                 cmdtxt(n->nbinary.ch2);
1143                 cmdputs("; done");
1144                 break;
1145         case NFOR:
1146                 cmdputs("for ");
1147                 cmdputs(n->nfor.var);
1148                 cmdputs(" in ...");
1149                 break;
1150         case NCASE:
1151                 cmdputs("case ");
1152                 cmdputs(n->ncase.expr->narg.text);
1153                 cmdputs(" in ...");
1154                 break;
1155         case NDEFUN:
1156                 cmdputs(n->narg.text);
1157                 cmdputs("() ...");
1158                 break;
1159         case NCMD:
1160                 for (np = n->ncmd.args ; np ; np = np->narg.next) {
1161                         cmdtxt(np);
1162                         if (np->narg.next)
1163                                 cmdputs(" ");
1164                 }
1165                 for (np = n->ncmd.redirect ; np ; np = np->nfile.next) {
1166                         cmdputs(" ");
1167                         cmdtxt(np);
1168                 }
1169                 break;
1170         case NARG:
1171                 cmdputs(n->narg.text);
1172                 break;
1173         case NTO:
1174                 p = ">";  i = 1;  goto redir;
1175         case NAPPEND:
1176                 p = ">>";  i = 1;  goto redir;
1177         case NTOFD:
1178                 p = ">&";  i = 1;  goto redir;
1179         case NCLOBBER:
1180                 p = ">|"; i = 1; goto redir;
1181         case NFROM:
1182                 p = "<";  i = 0;  goto redir;
1183         case NFROMTO:
1184                 p = "<>";  i = 0;  goto redir;
1185         case NFROMFD:
1186                 p = "<&";  i = 0;  goto redir;
1187 redir:
1188                 if (n->nfile.fd != i) {
1189                         s[0] = n->nfile.fd + '0';
1190                         s[1] = '\0';
1191                         cmdputs(s);
1192                 }
1193                 cmdputs(p);
1194                 if (n->type == NTOFD || n->type == NFROMFD) {
1195                         if (n->ndup.dupfd >= 0)
1196                                 s[0] = n->ndup.dupfd + '0';
1197                         else
1198                                 s[0] = '-';
1199                         s[1] = '\0';
1200                         cmdputs(s);
1201                 } else {
1202                         cmdtxt(n->nfile.fname);
1203                 }
1204                 break;
1205         case NHERE:
1206         case NXHERE:
1207                 cmdputs("<<...");
1208                 break;
1209         default:
1210                 cmdputs("???");
1211                 break;
1212         }
1213 }
1214
1215
1216
1217 STATIC void
1218 cmdputs(const char *s)
1219 {
1220         const char *p;
1221         char *q;
1222         char c;
1223         int subtype = 0;
1224
1225         if (cmdnleft <= 0)
1226                 return;
1227         p = s;
1228         q = cmdnextc;
1229         while ((c = *p++) != '\0') {
1230                 if (c == CTLESC)
1231                         *q++ = *p++;
1232                 else if (c == CTLVAR) {
1233                         *q++ = '$';
1234                         if (--cmdnleft > 0)
1235                                 *q++ = '{';
1236                         subtype = *p++;
1237                 } else if (c == '=' && subtype != 0) {
1238                         *q++ = "}-+?="[(subtype & VSTYPE) - VSNORMAL];
1239                         subtype = 0;
1240                 } else if (c == CTLENDVAR) {
1241                         *q++ = '}';
1242                 } else if (c == CTLBACKQ || c == CTLBACKQ+CTLQUOTE)
1243                         cmdnleft++;             /* ignore it */
1244                 else
1245                         *q++ = c;
1246                 if (--cmdnleft <= 0) {
1247                         *q++ = '.';
1248                         *q++ = '.';
1249                         *q++ = '.';
1250                         break;
1251                 }
1252         }
1253         cmdnextc = q;
1254 }